There are many digital modes in amater radio. The ones popular on handheld
VHF/UHF radios include:
- D-Star
- DMR
- System Fusion
- NXDN
- P25
To use these modes you typically need two things:
- a handheld radio that supports the mode you want to use
- a nearby repeater or reflector that supports the mode you want to use
There are many options for handheld radios. These repeaters are usually
connected to the internet which enables communications with others around the
world using that same mode. If there isn't a repeater in your area that
offers the digital mode you want to use, you are out of luck. Unless you have a
hotspot.
A hotspot is a pocket sized low power repeater that connects to the internet
and can communicate with your handheld using various digital modes. You can buy
commercial devices, or build your own with a Raspberry Pi, radio boards, and
open source software.
The Hamspot 5 by Collin K0NNK is a new option
which gives you the flexibility and upgradability of your own Raspberry Pi based
solution, without you having to do all the tinkering to get something that
works.
This looks like a great option, with full duplex operation and a nice looking
case. Runs from USB-C power, and connects to the internet via Ethernet or Wi-Fi.
〰〰〰
A couple months ago Wojciech Kaczmarski SP5WWP
announced the LinHT project.
These mad lads buy a Retevis C62 radio and replace all the circuit boards inside with
their own. They aim to create an open-source hardware, Linux based, SDR handheld
transceiver. Their first boot of the OS happened on August 18.
Last week, Wojciech, Andreas OE3ANC, and Vlastimil OK5VAS hit a major milestone: the
radio now works as a complete M17 transceiver.
A few days later, Vlastimil submitted a PR
for the first iteration of Revision B of the circuit boards, which includes:
- a 5W amplifier
- new audio codec
- a redesigned power system which can charge from USB-C with simultaneous operation of the radio
Rev B is not yet ready for manufacturing, but I'll be following closely and can't wait to buy one.
〰〰〰
Because the market for batteries to charge phones and laptops is so much larger
than the market for batteries we 12V output, all the innovation in batteries
is happening on batteries that have USB-C Power Delivery output. There are many
vendors and lots of products with different characteristics. If you want to use
these batteries with amateur radio gear that takes 12V, or that requires an
unusual voltage (my UV-5R battery charger wants 10V input), you have to:
- buy this cable from Adafruit which
asks the USB-C device for 12V
- connect it to a small buck converter or boost converter to get the voltage that you want
- live with the losses and heat of the buck/boost converter
Now there is another option, the PocketPD.
This small device allows you to choose the voltage you want, and it requests
that voltage from the connected USB-C power source. You need a modern USB-C power source
that supports the Programmable Power Supply mode from USB PD 3.0 and later. As you
would expect, there are many USB-C power sources that comply with this standard.
Instead of bucking or boosting the voltage from USB-C, this device just asks
the USB-C for exactly the voltage that you want. Very clever.
〰〰〰
